Browse Prior Art Database

Multilevel Bidirectional Signal Transmission

IP.com Disclosure Number: IPCOM000085023D
Original Publication Date: 1976-Feb-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Henle, RA: AUTHOR [+2]

Abstract

Computer wiring requirements are reduced by increasing the information handling capability of transmission lines, to provide for multilevel bidirectional signal transmission.

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Multilevel Bidirectional Signal Transmission

Computer wiring requirements are reduced by increasing the information handling capability of transmission lines, to provide for multilevel bidirectional signal transmission.

Examples of this include the simultaneous transmission on a single transmission line of a ternary signal in each direction or (with two additional levels) of the simultaneous transmission of two binary signals in each direction. By a suitable choice of drivers and receivers, lines also can be operated with a combination of signals. For example, A can send binary signals to B while B sends ternary signals to A.

When simultaneous transmissions exist in two directions, the sending and receiving points must be that same. That is, A can send to B while B sends to A, but A cannot send to B while B is transmitting to C (on the same line) since C would be unable to decode the A + B simultaneous transmissions. One sender can however send to a group of receivers on a line.

In the drawing, current sources I --> In are equal in magnitude. The value of R1 is equal to 1/2 the line impedance Z. Current source Iy is chosen such that Iy R1 provides the bias for the first level (the basis for each level is chosen to lie midway between the maximum and minimum voltages for a given level). Iy (R1 + R2) provides the bias for the second level and Iy (R1 + R2...Rn) the bias for the nth level.

Another design possibility includes the case where the paired currents (I1, I2)...